Introduction:
Paroxysmal dyskinesias and episodic
ataxias are often caused by mutations in genes related to cell membrane and synaptic function. Despite the exponential increase in publications of genetically confirmed cases, management remains largely clinical based on non-systematic evidence. Areas covered: The authors provide a historical and clinical review of the main types of
paroxysmal dyskinesias and episodic
ataxias, with recommendations for diagnosis and management of patients suffering from these conditions. Expert opinion: After secondary
paroxysmal dyskinesias, the most common paroxysmal
movement disorders are likely to be PRRT2-associated paroxysmal kinesigenic
dyskinesias, which respond well to small doses of
carbamazepine, and
episodic ataxia type 2, which often responds to
acetazolamide. Familial paroxysmal non-kinesigenic
dyskinesias are largely caused by mutations in PNKD and have poor response to
therapy but improve with age. Exercise-induced
dyskinesias are genetically heterogeneous, caused by disorders of
glucose transport, mitochondrial function, dopaminergic pathways or neurodegenerative conditions amongst others. GNAO1 and ADCY5 mutations can also cause paroxysmal
movement disorders, often in the context of ongoing motor symptoms. Although a therapeutic trial is justified for classic cases and in limited resource settings, genetic testing may help direct initial or rescue
therapy.
Deep brain stimulation may be an option for severe cases.